what is the composition of a helium 3 molecule?

Answer

Dear Stefan,

In order to answer this question, we need to point out the difference between an atom and a molecule. An atom is a building block for the matter around us, which is made up of a nucleus and around which a certain number of electrons move. The nucleus itself contains for a neutral atom as many protons as there are electrons and in addition there are a varying number of neutrons in the nucleus. If the number of protons varies, you are dealing with different atoms, eg an oxygen atom (8 protons), a hydrogen atom (1 proton) and an iron atom (26 protons). In this way you can encounter about 100 different atoms in nature. If an atom contains a different amount of neutrons for the same number of protons, it is called an isotope. eg. for the hydrogen atom (1 proton) three isotopes are known, namely hydrogen itself (no neutron in the nucleus), deuterium (1 neutron) and tritium (2 neutrons). A molecule, on the other hand, is a particle that is built up from a collection of atoms that are bound together in a specific way by relatively strong bonds, eg H2O (= 2 hydrogen atoms with one oxygen atom).

Well, helium 3 is also an atom and not a molecule, moreover it is an isotope of the helium atom that is most abundant and that in its nucleus contains 2 neutrons in addition to 2 protons. We could call this helium 4, then helium 3 means that this refers to an isotope of helium where we only have one neutron instead of two. The number therefore refers to the number of nuclear particles in fact, ie the sum of the number of protons and neutrons.

I hope this is useful as an explanation

Regards